Question

Induction type single phase energy meter is ________.

• A. a VA meter
• B. true watt-hour meter
• C. an ampere-hour meter
• D. wattmeter

Hint:

Induction meters measure watt-hours — real energy consumed. Not to be confused with VA meters or wattmeters!

Answer 1

The Correct Option is B

Step 1: Working of Induction Type Energy Meter
Induction type single-phase energy meters work on the principle of electromagnetic induction and are designed to measure energy in kilowatt-hours (kWh). They use two electromagnets: one connected to the voltage coil and another to the current coil.
Step 2: What Quantity Is Measured?
These meters measure the product of power consumed (W) and time (h), i.e., true energy consumed. The meter disc rotates proportionally to the energy consumed, and the total number of revolutions indicates the energy in kWh.
Step 3: Clarification of Options
- (1) VA meter → measures apparent power, not energy.
- (2) True watt-hour meter → correct, as it measures real energy.
- (3) Ampere-hour meter → used in batteries, doesn't measure energy directly.
- (4) Wattmeter → measures power, not energy over time.
Conclusion:
Option (2) is correct — an induction type single-phase energy meter measures true energy in watt-hours.